Termites that damage buildings and other structures are most commonly subterranean. Their attack/infestation originates from the nest (colonies) located either underground or in the base of trees, with tunnels (foraging galleries) radiating from the nest through the soil to food sources.
At all times termites require moisture but must conceal themselves from direct sunlight. Thus for travel across exposed faces of walls, for example, they build mud-like shelters (tunnels) “plasters” on the exposed faces in which they can travel, concealed from sunlight to their food source. The area for subterranean migration may comprise a crack, fissure, joint, opening, perpend, mortar joint, (and areas underneath termite barriers when installed across a masonry brick/block course to an external face of the building) or the like in an outer wall, footing or slab cavity.
Due to changes in government regulations in Australia and elsewhere, past methods of preventing termite attack or entry in buildings which have involved the use of many termiticides under the slab and around the outside periphery of a building is now no longer possible to employ because of the potentially detrimental effects of the residual termiticides. Whilst new termiticides or termite repellent chemicals have been introduced to overcome this problem, such chemicals prove considerably more expensive to use. As a result, a number of different methods have been proposed or are now used with the aim of combating termite infestation or migration.
An approach adopted in buildings having concrete slab is to form a physical termite barrier between the slab and the external masonry walls. The barrier is typically attached to the slab and across the wall cavity to an external wall and positioned at a mortar course above ground level.
One such method involves the use of a product known as TERMIMESH which comprises a mesh of stainless steel which has pores of sufficiently small size to prevent the passage of termites therethrough. The outer edge of the mesh is located in a mortar course of an external wall. Typically, a damp proof course may be applied on top of the mesh and then mortar and a subsequent masonry course are laid on top of the mortar.
In our earlier application, we provided a method of preventing or minimising migration of termites by applying a settable or curable termite or insect resistant barrier mixture which when applied cures to form a continuous flexible penetration resistant barrier which adheres to and extends between an above ground exposed portion of the outer wall skin and the slab.
With these techniques, the physical barriers generally terminate at or near the edge of a mortar course on the external masonry face. We have found that termites can breach such barriers through imperfections in the mortar or the masonry bricks/blocks and circumvent the physical barrier with a short “plaster” that simply extends across the edge of the barrier in a manner that makes the detection of such plasters difficult.
The present invention aims to overcome or alleviate at least one of the above disadvantages by providing improved methods of and means for preventing or minimising the passage or migration of termites or other insects into a building. Other objects and advantages of the invention will become apparent from the following description.